Room Analysis Primer - Page 2

DanDan · 26th January 2010

I believe the simple models of pressure and velocity/particle displacement are useful for their intended purposes.
However, if one logic is applied, one could conclude that porous absorbers are almost useless at boundaries. Clearly this is not the case. IMHO measurement, even consistent subjective observation trumps theory, so we need to bring the science up to speed.
More logic suggests that there are other mechanisms at work.
Let's take an example of a single Kick drum hit. The wavefront, with quite a wide frequency spectrum, begins it's journey from the speaker. When it reaches the boundaries it has to pass though the impediment of porous absorption, twice. Same again on every bounce. That's got to slow it down and diminish it.
That's my personal contribution, just a guess though.
I suspect there are other understandings and mechanisms at play also. Logic says so!

There are many discussions regarding tuned panel or membrane traps. Let's not forget Poly's either. No one bothers or perhaps it is impossible to come up with a single number efficiency indicator to compare these devices. This lack of 'value rating' means there will be never ending venturing of opinions as to which are best 'Munro uses membrane traps' and so on.
These things are all simply tools. A successful listening environment is a balance of compromises. There is also personal sonic taste to confuse matters. Ultimately I reckon a successful mix room is one where you don't get a shock when you hear your stuff outside in the real world. This translation is vital to get work done and is in my experience very much absent in many many commercial studios.
Recording is another matter altogether, I can certainly visualise the use of membrane, panel, and poly traps in such rooms.
DD

Seamus TM · 26th January 2010

Thanks, DanDan.
That makes sense to me.

SAC · 30th January 2010

The mysterious component that is missing in the discussion is the acoustic impedance of the boundary. The problem encountered in the forums is that all of the models are far too simple, and many , in the effort to avoid math or more complex aspects desire a simple model, thus neglecting many facets of significant importance.

Boundaries have an acoustical impedance which 'controls' the degree of absorption and reflection based upon the impedance termination mismatch - just as does an electrical signal.

26th January 2010	#31
DanDan Lives for gear Joined: Aug 2003 Location: Cork Ireland Posts: 6,825 Thread Starter 1 Review written	Logic all the way... I believe the simple models of pressure and velocity/particle displacement are useful for their intended purposes. However, if one logic is applied, one could conclude that porous absorbers are almost useless at boundaries. Clearly this is not the case. IMHO measurement, even consistent subjective observation trumps theory, so we need to bring the science up to speed. More logic suggests that there are other mechanisms at work. Let's take an example of a single Kick drum hit. The wavefront, with quite a wide frequency spectrum, begins it's journey from the speaker. When it reaches the boundaries it has to pass though the impediment of porous absorption, twice. Same again on every bounce. That's got to slow it down and diminish it. That's my personal contribution, just a guess though. I suspect there are other understandings and mechanisms at play also. Logic says so! There are many discussions regarding tuned panel or membrane traps. Let's not forget Poly's either. No one bothers or perhaps it is impossible to come up with a single number efficiency indicator to compare these devices. This lack of 'value rating' means there will be never ending venturing of opinions as to which are best 'Munro uses membrane traps' and so on. These things are all simply tools. A successful listening environment is a balance of compromises. There is also personal sonic taste to confuse matters. Ultimately I reckon a successful mix room is one where you don't get a shock when you hear your stuff outside in the real world. This translation is vital to get work done and is in my experience very much absent in many many commercial studios. Recording is another matter altogether, I can certainly visualise the use of membrane, panel, and poly traps in such rooms. DD

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread starter	Forum	Replies	Last Post
Room acoustic analysis software	mrclunk	Geekslutz forum	6	20th June 2009 02:40 AM
Room Analysis Mic Position?	GrooveToad	Studio building / acoustics	3	14th August 2008 06:05 PM
Bass Traps - but first room analysis	Bluzzi	So much gear, so little time!	13	31st July 2007 04:53 PM
Using FFT/Room analysis software	ethan_c	So much gear, so little time!	1	18th March 2006 04:07 PM
Room Analysis Results	redrue	So much gear, so little time!	20	23rd February 2006 07:09 PM

26th January 2010	#32
Seamus TM Lives for gear Joined: Aug 2004 Location: Upstate NY Posts: 1,607	Thanks, DanDan. That makes sense to me.

30th January 2010	#33
SAC Registered User Joined: Dec 2009 Posts: 2,622	The mysterious component that is missing in the discussion is the acoustic impedance of the boundary. The problem encountered in the forums is that all of the models are far too simple, and many , in the effort to avoid math or more complex aspects desire a simple model, thus neglecting many facets of significant importance. Boundaries have an acoustical impedance which 'controls' the degree of absorption and reflection based upon the impedance termination mismatch - just as does an electrical signal.